Hair Curler

ABSTRACT

A hair curler ( 1 ) includes a base body ( 2 ) including a center portion ( 3 ) being designed and arranged to support hair to be wound up. The hair curler ( 1 ) includes a first thermochromic substance ( 20 ) being designed and arranged to indicate a first temperature during a temperature increase of the hair curler ( 1 ) within a first temperature range by a first color change. The hair curler ( 1 ) includes a second thermochromic substance ( 35 ) being designed and arranged to indicate a lower second temperature during a temperature decrease of the hair curler ( 1 ) within a lower second temperature range by a second color change.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to co-pending German Patent ApplicationNo. DE 10 2008 007 539.6 entitled “Lockenwickler und seine Verwendung”,filed Feb. 5, 2008.

FIELD OF THE INVENTION

The present invention generally relates to a hair curler including abase body including a center portion being designed and arranged forwinding up human hair to attain curls. More particularly, the presentinvention relates to a hair curler including thermochromic substancesfor indicating temperatures by a color change.

BACKGROUND OF THE INVENTION

A hair curler is known from German Patent Application No. DE 198 43 800A1. The known hair curler includes a base body preferably being made ofplastic and being surrounded by a cover made of plastic foam. The covermade of plastic foam may include a thermochromic substance whichindicates a temperature by a color change during a temperature increase.

Hair curlers of various shapes and designs are also known from GermanPatent Application No. DE 102 41 772 A1 corresponding to US PatentApplication No. US 2004/0045573 A1, German Patent Application No. DE 19918 742 A1 corresponding to US Patent Application No. US 200210129830 A1and German Patent Application No. DE 37 13 280 A1. These hair curlers donot include a thermochromic substance.

SUMMARY OF THE INVENTION

The present invention relates to a hair curler for winding up humanhair. The hair curler includes a base body including a center portionbeing designed and arranged to support hair to be wound up. The haircurler includes a first thermochromic substance being designed andarranged to indicate a first temperature during a temperature increaseof the hair curler within a first temperature range by a first colorchange. The hair curler includes a second thermochromic substance beingdesigned and arranged to indicate a lower second temperature during atemperature decrease of the hair curler within a lower secondtemperature range by a second color change.

The novel hair curler allows the user of the hair curler to easily makethe correct decision when to stop blow-drying and how long to keep thehair curler in place before removing it. The novel hair curler isespecially suitable for use at home. However, the novel hair curler mayalso be used by professionals in hairdresser's shops.

A problem during use of known hair curlers is the determination of theperiod of time during which the hair curler needs to be kept in place atthe head after having wound up the hair. Usually, the next step afterwinding up is blow-drying taking place over a certain period of time andunder a temperature increase of the wound up hair and of the haircurler. This step serves to ensure stability of the curl. It is knownthat hair is deformable in its warm condition whereas this is not thecase in its cold condition. Usually, a cooling down period followsblow-drying. Cooling down is to be understood as a period of time duringwhich the hair curler simply stays in place at the head until it reachesthe desired cooler temperature. After the hair has cooled down, theunwinding process begins to attain permanently deformed curls of thedesired shape. If the unwinding process is started too early, there isthe danger of the shape of the curls being destroyed and beingnegatively influenced, respectively.

The novel hair curler includes a base body or a different portionincluding a first thermochromic substance and a second thermochromicsubstance. These thermochromic substances may be incorporated in thematerial of the base body such that the entire base body includes thethermochromic substances. However, it is also possible to only apply thethermochromic substances to a part of the base body. It is even possibleto use the thermochromic substances at an element of the hair curlerother than the base body, for example at a contact strip surrounding thebase body or at a transverse pin serving to fix the base body to thehead. The thermochromic substances may also be designed as coatingsbeing applied to at least a part of the base body or to a different partof the hair curler. This especially applies if the material of the basebody or of the different part of the hair curler is a comparatively hardplastic material or even metal. The thermochromic substances preferablyare located at a part of the base body or of a different part of thehair curler which can be easily seen with the eye after having wound uphair. Consequently, especially the end portions of the base body aresuitable for this purpose since these are the portions which are notcovered by hair, but by which the hair curler is handled after havingwound up the hair. It is also sufficient if only one of these endportions is covered with the thermochromic substances and thethermochromic plastic materials, respectively. It is also possible toarrange the first thermochromic substance in a first end portion of thehair curler and to arrange the second thermochromic substance in thesecond end portion of the hair curler. In this way, one end portionindicates the desired temperature during blow-drying, and the other endportion indicates the desired temperature during cooling down of thehair. The end portions may be designated in this way for easier handlingby the user, for example by an inscription or a label.

The choice of the specific thermochromic substances depends on thetemperature and the temperature range, respectively, during which theoccurring color changes are desired. It is to be understood that thesesubstances mostly change their color within a certain temperature rangeand not exactly at a specific temperature in a “digital” way. Forexample, during heating of the hair curler during blow-drying, it makessense to choose the first thermochromic substance such that the colorchange occurs within a temperature range of the curl and of the haircurler, respectively, of approximately between 40° C. to 60° C. Thistemperature range usually corresponds to a blow-drying time of 2 to 3minutes. In other words, it is common that approximately 50° C. arereached at the hair curler after 2 to 3 minutes. It is to be understoodthat this depends on the intensity of blow-drying, for example on thedistance between the blow-dryer to the hair. However, the desiredtemperature range is often attained after approximately 2 to 3 minutesof blow-drying resulting in stabilizing and fixing the curl of woundhair.

The first color change is used during a temperature increase to indicatewhen the temperature has been reached at which it makes sense to stopblow-drying to prevent temperatures which are too high and whichpossibly result in damages of the hair. In contrast thereto, the secondthermochromic substance causing the second color change becomeseffective during a temperature decrease as it makes sense to indicate alower temperature at the ending of the period of time during which thehair cools down. Usually, it is desired to attain cooling down times ofapproximately between 12 to 20 minutes during which the hair and thehair curler reach approximately room temperature or preferably atemperature slightly above room temperature, especially a temperaturebetween 20° C. and 30° C., and preferably a temperature approximatelybetween 24° C. and 27° C.

The first thermochromic plastic is added to improve handling ofblow-drying. The second thermochromic plastic is used to improve handingduring cooling down. In this way, the ending of both processes isclearly indicated to the user by and color change easily visible withthe eye.

The base body may include approximately between 2% to 6%, especiallyapproximately 4%, of each of the two thermochromic plastic materials.For example, the thermochromic plastic materials may be mixed with thebase material of the base body.

Suitable materials for producing the base body are plastic materialssuch as polypropylene, polyethylene, polystyrene, acrylic styrene,polyvinyl chloride, polyamide, polyethylene terephthalate, and the like.These materials may be used for base bodies being produced by injectionmolding as well as for base bodies being made of a respective plasticfoam. The plastic foams may be especially polyethylene foam, ethylenevinyl acetate foam, polyurethane foam, polyether amide block copolymerfoam, polyester amide block copolymer foam and polyether foam.Especially, materials including approximately 92% of polypropylene and8% of thermochromic substances have shown positive results. Especially,the thermochromic substances may be made of approximately 82% ofpolypropylene and approximately 18% of microencapsulated thermochromicsubstances. The thermochromic substances may also be polyethylene,polypropylene, polystyrene, and the like.

Other features and advantages of the present invention will becomeapparent to one with skill in the art upon examination of the followingdrawings and the detailed description. It is intended that all suchadditional features and advantages be included herein within the scopeof the present invention, as defined by the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be better understood with reference to the followingdrawings. The components in the drawings are not necessarily to scale,emphasis instead being placed upon clearly illustrating the principlesof the present invention. In the drawings, like reference numeralsdesignate corresponding parts throughout the several views.

FIG. 1 is a perspective view of a first exemplary embodiment of thenovel hair curler.

FIG. 2 is a sectional view through the hair curler according to FIG. 1in its winding end position close to the scalp of a human head.

FIG. 3 is a sectional view through a second exemplary embodiment of thenovel hair curler including three interconnected elements.

FIG. 4 is a perspective view of a third exemplary embodiment of thenovel hair curler.

FIG. 5 is a sectional view through a fourth exemplary embodiment of thenovel hair curler.

FIG. 6 is a sectional view along line VI-VI in FIG. 5.

FIG. 7 is a sectional view along line VII-VII in FIG. 5.

FIG. 8 is a side view of a fifth exemplary embodiment of the novel haircurler.

FIG. 9 is a view of the hair curler according to FIG. 8 with a wound upcurl and bent end portions.

DETAILED DESCRIPTION

Referring now in greater detail to the drawings, FIG. 1 illustrates afirst exemplary embodiment of the novel hair curler 1. The hair curler 1includes a base body 2 being designed as a form body made of plastic,metal, and the like. Preferably, the base body 2 is designed to behollow. As seen in an axial direction, the base body 2 includes a centerportion 3 and two fixing portions 4 being arranged at its ends. The twofixing portions 4 have the same diameter being greater than the diameterof the center portion 3. In this way, the hair curler 1 has the shape ofa coil or a roller with end portions extending in a radial outerdirection. Preferably, the entire axial extension of the circumferenceof the fixing portions 4 is covered by a hook band 5. Such hook bands 5are known as parts of Velcros. They include a woven or seemed portionincluding outwardly protruding spikes or hooks 6. Especially, the hooks6 may be designed as loops which have been opened by cutting. The centerportion 3 and also the fixing portions 4 at the base body 2 may includea multitude of openings 7.

FIG. 2 illustrates the wound up position of the hair curler 1 at a humanhead 8 in the region of the scalp 9. The hair at the scalp 8 is notillustrated. Only one wound up part of hair is schematicallyillustrated, the part being wound up to attain a curl 10. It is to beunderstood that the winding operation of such a curl 10 begins at thetips of the hair. A portion of a spike band 11 is located in the regionof the center portion 3. The spikes of the spike band 11 are designed tobe shorter in a radial direction compared to the hooks 6 of the hookband 7 being located in each one of the fixing portions 4. The spikeband 11 only extends over a certain portion of the axial length of thecenter portion 3. It serves to fixedly arrange the tips of the hair inthat portion and to begin the winding process. Due to the increase ofthe diameter of the center portion 3 compared to the two fixing portions4, it is ensured that the curl 10 being attained from winding up thehair is only arranged in the center portion 3, and it attains a certainwinding thickness in this portion. During winding, the hook band in bothfixing portions 4 remains free from hair. As soon as the hair curler 1approaches the scalp 9 during winding and the winding process iscompleted, the hair curler 1 is pressed against the scalp 9. Thisposition is illustrated in FIG. 2. The hooks 6 of the two hook bands 5of the two fixing portions 4 engage the hair at the hair line close tothe scalp 9 such that the hair curler 1 attains its predetermined fixedposition close to the scalp 9. Due to the increase of the diameter ofthe smaller diameter of the center portion 3 compared to the greaterdiameter of the fixing portions 4, one attains room for a certainwinding thickness of the curl 10. Despite this fact, due to theincreased diameter of the fixing portions 4, there is the possibility ofmaintaining the fixed position at the head 8 even when this has a rounddesign in many portions. The wound up hair forming the curl 10 at thehair line are not bent, but they can instead extend between the root ofthe hair and the winding location at the circumference of the curl 10 ina radial position with respect to the head 8 having a positive influenceon the full design of the curl 10. However, even in this winding endposition, there still is a free space allowing for passage of air suchthat the portion of the curl 10 facing the scalp 9 can also be aeratedand dried after having wound up the hair in their wet condition.

The hair curler 1 according to FIG. 2 may especially have the followingdimensions. The center portion may have a diameter of approximatelybetween 12 mm and 32 mm. The center portion 3 may especially extend overan axial length of approximately between 13 mm and 40 mm. The two fixingportions 4 may especially have a diameter 14 of approximately 40 mm, andthey may have an axial length 15 of approximately 10 mm. The hooks 6 mayhave a length of approximately 3 mm in a radial direction. The spikes ofthe spike band 11 may have a length of approximately 1.5 mm.

The base body 2 of the exemplary embodiment of the novel hair curler 1according to FIG. 2 is designed as a one piece form body. Only the twosections of the hook band 5 and the spike band 11 are separate piecesbeing connected to the base body 2 by welding in the sense ofsimultaneously interconnecting the two ends of each band section.

FIG. 3 illustrates an exemplary embodiment of the novel hair curler 1having a smaller size and serving for winding up a shorter portion ofhair on a smaller diameter. The hair curler 1 includes three elements.The base body 2 is formed by a tube section 16 continuously extendingover the axial length of the hair curler 1 and two rings 17 beingconnected to the tube section 16. The connection may be realized bygluing or by a snap fit. The rings 17 then form the fixing portions 4,and they realize the increase of the diameter compared to the centerportion 3. The center portion 3 may include a ribbing 18 to simplifyconnection of the hair at the beginning of the winding process. Therealso is the possibility of arranging sections of hook bands 5 or hooks 6directly on the rings 17. The ratio of the diameters and of the lengthsis chosen to differ from the above described embodiment. The hair curler1 has a comparatively small size. The increase of the diameter is alsosmaller compared to the embodiment of the hair curler 1 illustrated inFIG. 2.

The base body 2 of the hair curl 1 is made of a material 19. Preferably,the material 19 is plastic. Suitable kinds of plastic are polypropylene,polyethylene, polystyrene, acrylic styrene, polyvinyl chloride,polyamide, polyethylene terephthalate, and the like, or a respectiveplastic foam. The material 19 forming the base body 2 may be mixed witha first thermochromic substance 20 and/or a second thermochromicsubstance 35. It is possible that the entire base body 2 of the haircurler 1 according to FIG. 1 or only a part thereof is made of thismaterial 19.

In the exemplary embodiment of the hair curler 1 according to FIG. 2, aplastic material is used in the region of the hook band 5 and/or in theregion of the hooks 6, the material corresponding to the material 19 ofthe base body 2, but including a first thermochromic plastic material 21and a second thermochromic plastic material 36. It is also possible touse a coating of such thermochromic plastic materials 21, 36 at thisplace. The exemplary embodiment of the hair curler 1 illustrated in FIG.2 shows that the thermochromic plastic materials 21, 36 may also belocated at a different portion of the hair curler 1 other than the basebody 2.

In the exemplary embodiment of the novel hair curler 1 according to FIG.3, the rings 17 may be made of a material to which the thermochromicplastic materials 21, 36 have been added. It is also possible to onlycover the rings 17 with such materials on the outer side.

FIGS. 4 to 7 illustrate another exemplary embodiment of the novel haircurler 1. The hair curler 1 also includes a base body 2. In this case,the base body 2 has a conical shape and a shape of a truncated cone,respectively. The hair curler 1 and the base body 2, respectively,extend over their length from a beginning end 22 to the other end 23.The beginning end 22 is designated as the end having the greatercross-section. As it is already to be seen in FIG. 4, the base body 2and thus the hair curler 1 at its beginning end 22 has an ovalcross-section being comparatively great and continuously diminishingtowards its other end 23. Especially, the base body 2 may be designed asa hollow body. It may be made of plastic or metal and it usually hassufficient stability and stiffness. The base body 2 may be designed toinclude openings similar to a grate along its entire length, or it mayinclude circular openings 7, for example. The base body 2 and the haircurler 1, respectively, in the region of its other end 23 include anenlarged portion 24. In the illustrated example, the enlarged portion 24is designed as a spherical protrusion. The enlarged portion 24 may bedesigned as one piece with the base body 2 by injection molding. Theenlarged portion 24 has a greater diameter than the base body 2 in theregion of its other end 23. The enlarged portion 24 fulfills twofunctions. It prevents hair from slipping down during winding orafterwards. On the other hand, the enlarged portion 24 of the haircurler 1 simplifies handling of the hair curler 1 to simplify winding ofhair.

On the outer circumference of the base body 2, especially beginning atits beginning end 22, and extending over a certain length of the basebody 2, a section of a hook band 5 is arranged and fixed. The hook band5 has a design as it is known from Velcros, for example. The hook band 5includes separate hooks 6 extending approximately in a radial directionor spikes having a mushroom shape at its circumference. The strip ofhook band 5 in the exemplary embodiment of the hair curler 1 illustratedin FIG. 4 approximately has half the length of the axial length of thehair curler 1 and of the base body 2, respectively. However, it is alsopossible to design the hook band 5 to be shorter or longer.

A fixing unit 25 is associated with the hair curler 1. In theillustrated exemplary case, the fixing unit 25 includes a needle 26being designed and arranged to be inserted through a respective opening7 in the base body 2 in a transverse direction when the winding processof the hair has been completed.

Possible designs of the cross-section of the hair curler 1 in accordancewith the exemplary embodiment of FIG. 4 are illustrated in FIGS. 5 to 7.

The base body 2 illustrated in FIGS. 4 to 7 is also completely or partlymade of thermochromic plastic materials 21, 36. Instead or additionally,it is also possible to arrange the thermochromic plastic materials 21,36 in the region of the enlarged portion 24 or even only in the regionof the needle 26, meaning at such locations which can be freely seen bythe user when hair is wound up on the hair curler 1 to allow for seeingthe color change during hair drying or after cooling of the hair.

The exemplary embodiment of the novel hair curler 1 illustrated in FIGS.8 and 9 includes a base body 2 being made of resilient plastic foamhaving a certain degree of restoring properties. The base body 2 has abar-like, elongated shape and a cross-section which is either circularor approximately square along its entire length. The base body 2 has asurface which may be designed to be open-pored and rough such that thehair to be wound engage this surface and are captured by this surface. Aflexible wire mesh 27 is located inside of the base body 2, meaning apiece of flexible wire which can be permanently deformed. The two ends28 of the wire mesh 27 are bent or deformed similar to a hook to reducethe risk of injuries. The wire mesh 27 in its middle portion may besurrounded by a tube section 29 by which the wire mesh 27 is enforced.When supplying forces in a normal range, the middle portion of the wiremesh 27 cannot be bent, whereas the end portions 30 are flexible. Inthis way, the base body 2 has a stiff center section 31 not beingflexible and end sections 32 being flexible. The plastic foam materialof the base body 2 continuously extends over the length such that thedifferences of the flexibility only result from the wire mesh 27.However, it is also possible not to arrange the tube section 29 suchthat the base body 2 has a generally bent shape. A portion of hair 33can be rolled in the center section 31 of the hair curler 1 to attain acurl.

In the exemplary embodiment of the novel hair curler 1 illustrated inFIG. 8, the material of the plastic foam includes the firstthermochromic substance 20, especially the thermochromic plastic 21, andthe second thermochromic substance 35, especially the thermochromicplastic 36.

Alternatively or additionally, the surface of the base body 2 mayinclude a coating 34 including these substances 20, 35, or thesesubstances 20, 35 may be arranged in the region of the end portions 32.

These thermochromic substances 20, 35 may also be used in cases when thebase body 2 or a different element of the hair curler 1 is not made ofplastic, but instead of metal, for example, especially when it is madein the form of a wire grate and the like.

The following applies to all illustrated exemplary embodiments as wellas additional embodiments of the novel hair curler. The material 19 ofthe base body 2 or of a different portion of the hair curler 1 may beplastic, especially plastic produced by injection molding. The plasticmay also be applied as plastic foam, especially as illustrated in theembodiments of FIGS. 8 and 9. The plastic may be polypropylene,polyethylene, polystyrene, acrylic styrene, polyvinyl chloride,polyamide, polyethylene terephthalate, and the like. The plastic mayalso be used in the shape of foam.

The first thermochromic substance 20 may be especially a thermochromicplastic 21. The second thermochromic substance 35 may be especially athermochromic plastic 36. Preferably, the thermochromic substances 20,35 only form a part of the material, or they are applied in the form ofa coating 34. It is also possible to use such a coating 34 on a needle26 of the fixing unit 25, for example.

Many variations and modifications may be made to the preferredembodiments of the invention without departing substantially from thespirit and principles of the invention. All such modifications andvariations are intended to be included herein within the scope of thepresent invention, as defined by the following claims.

1. A hair curler for winding up human hair, comprising: a base body,said base body including a center portion being designed and arranged tosupport hair to be wound up; a first thermochromic substance, said firstthermochromic substance being designed and arranged to indicate a firsttemperature during a temperature increase of said hair curler within afirst temperature range by a first color change; and a secondthermochromic substance, said second thermochromic substance beingdesigned and arranged to indicate a lower second temperature during atemperature decrease of said hair curler within a lower secondtemperature range by a second color change.
 2. The hair curler of claim1, wherein said base body is made of plastic and said firstthermochromic substance is a first thermochromic plastic and said secondthermochromic substance is a second thermochromic plastic.
 3. The haircurler of claim 2, wherein said first thermochromic plastic and saidsecond thermochromic plastic are mixed with said plastic of said basebody.
 4. The hair curler of claim 2, wherein said first thermochromicplastic is a material indicating the first temperature by the firstcolor change after blow-drying the hair for approximately 2 to 3minutes.
 5. The hair curler of claim 2, wherein said secondthermochromic plastic is a material indicating the lower secondtemperature after cooling down for approximately 12 to 20 minutes afterblow-drying the hair.
 6. The hair curler of claim 5, wherein said secondthermochromic plastic is a material indicating the lower secondtemperature after cooling down for approximately 12 to 20 minutes afterblow-drying the hair.
 7. The hair curler of claim 1, wherein said basebody is made of a material including approximately between 2% and 6% ofsaid first thermochromic substance and approximately between 2% and 6%of said second thermochromic substance.
 8. The hair curler of claim 2,wherein said first thermochromic plastic and said second thermochromicplastic are mixed with the plastic of a part of said hair curler otherthan said base body.
 9. The hair curler of claim 2, wherein said firstthermochromic plastic and said second thermochromic plastic are designedas at least one coating of said base body.
 10. The hair curler of claim2, wherein said first thermochromic plastic and said secondthermochromic plastic are designed as at least one coating of a part ofsaid hair curler other than said base body.
 11. The hair curler of claim2, wherein said base body is made of at least one plastic materialselected from the group consisting of polypropylene, polyethylene,polystyrene, acrylic styrene, polyvinyl chloride, polyamide andpolyethylene terephthalate a respective plastic foam.
 12. The haircurler of claim 11, wherein said base body is made plastic foam.